Photography is not my field professionally, but in the field that I'm in (experimental physics) education is pretty much meaningless except for two things; it shows you can tackle a large project (PhD) and that you can stick with something for a few years. It's just a barrier to entry (you must have a PhD to apply for the job). Other than that, what you really want is what can't be assessed and isn't taught. I want post-docs to be creative, have good spatial perception, and be hard working. Everything else can be learnt on the job pretty easily.
So my question is, do aspiring photographers need a degree to be an assistant for one of the big photographers, or is it more of a "who you know" type scenario? When you talk about being "qualified for entrance" are you talking about formal qualifications, or more informal qualifications (like being hard working and willing to learn, not being a jerk, etc.)?
The portfolio is the credential.
Many portfolios are kept under wraps, only to be shown to prospective clients. Much work is on websites but, many of us deliver samples on a thumb drive avoiding the web.
Any student (anyone) photographer looking for a job will have a portfolio and resume.
The photos in a portfolio will tell the story of the photographer's creative ability and technical skill. The resume will outline previous work experience. Formal schooling isn't necessary. It's all in the eye. If I was going to school with the idea of being a photographer today, I would major in math (so I could get a job out of school) and minor in Art History and languages.
Photo assistants come in levels that have to do with their technical skill and experience. Many photographers (people like Penn) have several assistants. The tiered progression would be: Studio Manager, 1st assistant, and those below .. some may be full time employees or contract hires. Some of the best and most expensive assistants are contract hires. They like variety and often have specialized skills.
I can tell you about me.. I know that material best.
I had a couple of photo classes in college. I was an unsatisfied science student. I built a portfolio over several years. I didn't have much camera gear but managed. I had access to a couple of darkrooms and made prints.
I landed an assistant's job with NatGeo, working in Italy. When I returned to the States I was hired for an 18 month assignment documenting the living conditions of Native Americans. It didn't pay well but, I enhanced my portfolio of work greatly. I did several memorable portraits, and that stayed with me.
I then worked in a very large professional photo lab as the Tech. My math science skills got me that job, not my pictures. After about a year, I made a deal with the boss, to get time off to do photo work in exchange for not paying me any over time. My overtime hours were accumulated and used for week days off. I used the days off to show my portfolio to graphic designers and art directors.
I began getting jobs and saved the money and bought additional camera gear for work use. After a year of this, I found I needed to learn lighting in a serious way. I showed my book (portfolio) to Irving Penn's former studio manager and I got lucky. I wanted to learn Penn's lighting and found a place to learn it. I worked there off and on for two years, while taking occasional assignments. Some of the art directors I met while working for Penn's former employee hired me once I was off on my own.
I worked very hard, I learned about a lot of stuff I would never use (8x10), but got good at it; it was my job to be good at everything needed. I was an ace at sorting cornflakes for food shots.. stuff like that.
I look for the same stuff in someone I would consider hiring. The assistant I had most recently was a grad of Brooks Institute, before it went into the dumper. Her dad did electronics and other tech work, so she's great with tools and lighting hardware.
One former assistant is a very successful food photographer. She too was a Brooks grad.
Hope that helps, I'm tired of writing.
I spent some time in, what was then called, UC LBL Bldg.51... if you know that place? I wish I had taken photos when the Bev was down. Math is still a hobby.
pkr